private string PrepareQuery(FindMatchingOrganisations query)
{
var returnString = query.CompanyName.Trim().ToUpperInvariant();
foreach (var specialCase in specialCases)
{
specialCase.CleanseSpecialCases(ref returnString);
}
return(returnString);
}
public async Task <IList <OrganisationData> > HandleAsync(FindMatchingOrganisations query)
{
var searchTerm = PrepareQuery(query);
// This search uses the Levenshtein edit distance as a search algorithm.
var permittedDistance = CalculateMaximumLevenshteinDistance(searchTerm);
var possibleOrganisations = await GetPossibleOrganisationNames(searchTerm);
var uppercaseOrganisationNames =
possibleOrganisations.Select(o => new KeyValuePair <string, Guid>(o.Name.ToUpperInvariant(), o.Id))
.ToArray();
// Special cases should be ignored when counting the distance. This loop replaces special cases with string.Empty.
for (var i = 0; i < possibleOrganisations.Length; i++)
{
foreach (var specialCase in specialCases)
{
specialCase.CleanseSpecialCases(ref uppercaseOrganisationNames[i]);
}
}
var matchingIdsWithDistance = new List <KeyValuePair <Guid, int> >();
for (var i = 0; i < possibleOrganisations.Length; i++)
{
var distance = StringSearch.CalculateLevenshteinDistance(searchTerm, uppercaseOrganisationNames[i].Key);
if (distance <= permittedDistance)
{
matchingIdsWithDistance.Add(new KeyValuePair <Guid, int>(uppercaseOrganisationNames[i].Value,
distance));
}
}
matchingIdsWithDistance = matchingIdsWithDistance.OrderBy(m => m.Value).ToList();
var matchingOrganisations =
matchingIdsWithDistance.Select(
m => possibleOrganisations.Single(o => o.Id == m.Key));
return(matchingOrganisations.Select(o =>
new OrganisationData
{
Id = o.Id,
Name = o.Name
}).ToList());
}
